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A DC distribution system integrated with electric vehicle charging stations (EVCSs) is typically constructed to satisfy the large power exchange demands of electric vehicles (EVs). However, the stochastic operating state of the EVCSs results in difficulties in the stability analysis of the DC distribution system. In this study, a linearized model of the DC distribution system connected with multiple EVCSs is established, which considers the charging and the discharging states of the EVCSs. Based on the similarity transformation, this study theoretically verifies the generalized conclusion that a DC distribution system has a higher possibility of instability if the EVCSs are in the charging rather than the discharging state, and that the system stability is the worst if all the EVCSs operate at the maximum charging state. Moreover, a method to quickly evaluate the stability region of the DC distribution system is proposed. It can provide a numerical instability risk estimation of a complex DC distribution system considering all the possible states of the EVCSs. Lastly, the conclusions are validated by two SIMULINK cases, and the application of the numerical instability risk estimation to the DC distribution system is demonstrated.

In this paper, an important application of Interconnected microgrids (IMGs) is presented in order to handle an emergency condition of individual microgrids (MGs), which causes an intolerable voltage magnitude or frequency deviation. In this method, the active and reactive powers are exchanged via an interlinking back-to-back converter (BTBC) and in accordance with voltage magnitude and/or frequency differences of individual MGs. In order to increase the IMG reliability and overcome the communication challenges, only local voltages and frequencies of both AC sides of the BTBC are used to determine the required active and reactive powers to be exchanged. A generalized droop control is employed to consider the impact of voltage magnitude and frequency differences on exchanging active and reactive powers separately for any type of interlinking lines. In this emergency power exchange method, a logical control is employed to detect the emergency condition, which results in the IMG formation, as well as to detect the normal condition and form the individual MGs operation again. The real-time results, obtained from OPAL-RT simulator, practically show advantages of the proposed method including voltage and frequency supports, postponing the load shedding, plug-and-play capability, good power sharing between the IMGs and method compatibility with the controls of individual MGs.

This paper investigates the pricing issue of power exchange options with default risk, in which the dynamics of the underlying assets and the counterparty asset follow three correlated stochastic v...

Electric vehicles (EV) are the inevitable future of the transportation industry considering the current energy scenario and all the incentives and benefits they provide. Nonetheless, EVs exhibit a ...

We review the variational formulation of nonequilibrium thermodynamics as an extension of the Hamilton principle and the Lagrange-d’Alembert principle of classical mechanics. We focus on the case of open systems that include the power exchange due to heat and matter transfer, with special emphasis on reacting systems which are very important in biological science.

In this article, we propose a jump diffusion framework to price the power exchange options. We model the price dynamics of assets using a Hawkes jump diffusion model with common factors to describe the correlated jump risk and clustering of asset price jumps. In the proposed model, the jumps, reflecting common systematic risk and idiosyncratic risk, are modeled by self-exciting Hawkes process with exponential decay. A pricing formula for valuation of power exchange option is obtained following the measure-change technique. Existing models in the literature are shown to be special cases of the proposed model. Finally, sensitivity analysis is given to illustrate the effect of jump risk and jump clustering on option prices. We observe that jump clustering significantly effects the option prices.

With a high penetration level of renewable energy resources (RESs) in the distribution network (DN) and microgrids (MGs), how to realise the coordination between the two entities while takes the uncertain RESs into consideration becomes an urgent problem. A data-driven distributionally robust economic dispatch (DRED) model for both DN and MGs is proposed in this study, wherein the 1-norm and ∞-norm are used to construct the confidence set for the probability distribution of the uncertainties based on historical data. The DN and each MG are considered as independent entities to minimise their own operation cost. The alternating direction method of multipliers is utilised to coordinate the power exchange between DN and MGs and realise the autonomy of each entity. The column and constraint generation algorithm is used to solve the proposed data-driven DRED model for each entity. Considering the special structure of the proposed DRED problem, a duality-free decomposition method is adopted. Thus the computational burden is reduced. Numerical results on a modified IEEE 33-bus DN with three MGs validate the effectiveness of the proposed method.

What is the impact of blockchain technology on electronic markets in the energy sector? In this interview with Electronic Markets, Dr. Tobias Paulun, chief strategy officer of the European Energy Exchange (EEX), explains where the leading European energy exchange recognizes potentials of blockchain technology compared to existing electronic platforms and which blockchain projects EEX is working on. In his view, the impact of blockchain technology depends on the respective market segment and on the availability of solutions for safeguarding guarantees of origin. He expects that established exchange systems and blockchain-based systems will coexist in this strongly regulated and specialized industry.

Challenges of microgrids (MGs) energy management have gained more relevance with the presence of uncertainties in power generation and local loads. These problems significantly increase when related to network of smart MGs (NSMG). To address these challenges, this study presents a stochastic constrained control problem for the optimal management of a cooperative NSMG with interconnections allowing power exchanges. In this model, each MG can exchange power locally among each other as well as with the main electric grid. The proposed control approach is based on a linear-quadratic Gaussian problem definition for the optimal control of power flows under quadratic constraints limiting the variability of the power exchange as well as of the stored energy in each MG. The developed framework is applied to a cooperative network of four smart MGs to test and validate its effectiveness and performance. The network is connected to the main electric grid allowing power exchanges. The results demonstrate that the role of energy storage systems is undoubtedly becoming more and more relevant in the context of reacting to the stochastic behaviour of the balance between produced and consumed powers in MGs.

The electricity tariff is a powerful tool to encourage customers to modify their electricity consumption behavior. A significant portion of power energy is devoted to the commercial sector which has a notable contribution in the power grid peak load. In this article, we consider a commercial customer equipped with a solar panel and batteries as our case study. We analyze the effects of time of use (TOU) and maximum demand (MD) tariffs on the power exchange. Next, the sensitivity analysis of the load profile to the MD and battery characteristics is performed. Using the optimization and sensitivity analysis information, the optimum MD tariff rates for a group of the commercial customers is calculated to release the maximum network capacity in the power grid. The optimization in this study is formulated such that the interests of both the customers and the utilities are served.

The strategic intent of the African Union is to develop a “Smart Integrated African Electric Power Super Grid” driven by modern tools and advances in high-voltage direct current (HVDC) engineering and flexible alternating current technology systems (FACTS), which is central in supporting Africa’s sustained economic growth and development. The southern African region, including South Africa, is beset by the critical challenges of perennial load-shedding, which impedes economic growth and aggravates unemployment. This has led to the insecurity of electricity supplies and degraded the quality of life. The parallel operation of high-voltage direct current (HVDC) and flexible AC technology systems (FACTS) controllers is gaining traction as system conditions become more complex, such as weak power networks which requires increased stability requirements, resulting in load-shedding and power outages. These adversely affect business productivity and adversely affect GDP and economic growth. Thus, the application of innovative technologies such as HVDC links can stabilize weak power systems. It is established that HVDC delivery systems reduce losses in long transmission lines transporting bulk power compared with high-voltage alternating current (HVAC) transmission lines for power wheeling. This paper evaluates the parallel operation of the Cahora Bassa 1414 km bipolar HVDC link and a weak parallel 400/330 kV alternating current (AC) link. It demonstrates the use of FACTS controllers to enhance the technical performance of an existing network, such as voltage control, and technical loss reduction. It combines an HVDC line commutated converter (LCC) and HVAC transmission lines, in hybrid notation to increase the voltage stability of the system by controlling the reactive power with a Static Var Compensator (SVC). These modern tools can increase the transmission power controllability and stability of the power network. In this study, HVDC–LCC was used with a setpoint of 1000 MW in conjunction with the 850 MVAr SVC. The results show that the technical losses were reduced by 0.24% from 84.32 MW to 60.32 MW as Apollo 275 kV SVC was utilized for voltage control. The network analysis was performed using DIgSILENT PowerFactory software that is manufactured by DIgSILENT GmbH at Gomaringen, Germany

A 2000-es evektől napjainkig komoly atalakulas tortent a magyar arampiacon. A szerzők cikkukben a piacliberalizaciora koncentralva az elmult 15 ev folyamatait tekintik at. Megvizsgaljak, hogy az erteklanc egyes elemei menten (termelői oldal, kereskedelem), hogyan valosult meg a piacnyitas, mikor es hogyan harultak el az akadalyok, es valt lehetőve a valodi nagykereskedelmi verseny. A piacnyitas hatekonysagat tobb teruleten ertekelik: a beruhazasok es az arak alakulasa, az import szerepe, valamint ehhez kapcsolodoan az ellatasbiztonsag szempontjabol. A piacnyitas előkeszitesenek fontos elemei voltak a vertikalisan integralt vallalat uzletagainak szetvalasztasa es a privatizacio. A hosszu tavu szerződesekről az uzleti alapu műkodesre valo atteres es a 2001. es 2007. evi villamosenergia-torvenyek hatalyba lepese felszamolta a versenyző arampiac kialakulasa előtt allo akadalyokat. A hatekony nagykereskedelmi verseny megteremteseben kulcsszerepet jatszott az importkapacitasokhoz valo hozzaferes, es szinten fontos szerepe volt a magyar aramtőzsde, a HUPX letrejottenek, amely transzparens arjelzest szolgaltatott – es szolgaltat a mai napig – mind a hazai, mind a tőlunk delre elhelyezkedő orszagok szamara. Bar Magyarorszag – elsősorban a piac-osszekapcsolasok segitsegevel – nagy utat tett meg a nemzetkozi integracio fele, a hazai nagykereskedelmi arak maig jelentős felarat tartalmaznak a referenciapontkent ertelmezhető nemet piachoz kepest. --------- From the 2000’s until today, much has changed on the Hungarian electricity wholesale market. In this article the authors present an overview of market liberalisation efforts of the past 15 years across different market segments (supply side, trade); how and when barriers were eliminated and conditions of real wholesale market competition emerged in the Hungarian power market. The efficiency of market opening is evaluated according to different areas including development of investments and prices, role of imports and, in connection with the latter, security of supply. Unbundling and privatisation was key for creating the proper market structure as the basis of liberalization. The new power market laws (in 2001 and 2008) and the abolishment of LTCs in 2008 were important factors to facilitate competition. Access to import capacities also played a key role. A major element in market opening was the establishment of the Hungarien Power Exchange (HUPX), bringing transparent price signals for Hungarian and Balkan market participants. Though Hungary has come a long way towards regional market integration (mainly through market couplings), a significant spread still remains between Hungarian and (the reference) German power prices.

Most Electric Power Exchange (PX) around the world employs Linear Programming (LP) based method for step-wise market clearing in Day-Ahead Electricity Market (DAM). Market clearing involves calcul...

This paper replicates the study by Viehmann (2011) that investigated risk premia in the German day-ahead electricity market from October 2005 to September 2008. While estimated sizes of risk premia can be replicated, this paper does not reproduce respective standard errors, leading to remarkable differences between the reported significance levels. An extension with data of preceding years points to further differences with respect to size and statistical significance. In addition, this paper analyzes the impact of negative prices on risk premia. Negative electricity prices were introduced in 2008 at the European Power Exchange (EPEX), and in 2013 at the Energy Exchange Austria (EXAA). The results of an econometric analysis suggest that the introduction of negative prices has led to a decrease in risk premia when compared to the period of a positive price regime.

In this article, we study the valuation of a European vulnerable power exchange option in an intensity based framework. We assume that the default by the counter-party is the time of the first jump of a doubly stochastic Poisson process whose intensity is modeled by a jump–diffusion process. The dynamics of the two assets are assumed to be driven by correlated jump–diffusion processes. All the three processes are assumed to be correlated in continuous part as well as in the jump part. In the proposed framework, employing the measure-change technique, we obtain the explicit formula for the price of the power exchange option with counter-party risk. Furthermore, sensitivity analysis is given to illustrate the effects of counterparty risk on the price of the option and effect of various parameters on the option prices.

Jelenleg Magyarorszagon a villamosenergia piacot erdemes vizsgalni, mivel az elmult ev adatait attekintve valtozasok kovetkeztek be. Jelenleg a magyar villamosenergia piacot a HUPX ZRt. műkodteti, mely a kozep-kelet-europai regioban eleg magasan szinten elismert. A HUPX ZRt. celja a szervezett villamosenergia-piac magyarorszagi műkodtetese a magyar villamos energia torveny es a Magyar Energia Hivatal altal kiadott engedelyek rendelkezesei alapjan. A műkodtetesenel fő cel a legkorszerűbb villamosenergia-kereskedesi platformjainak az alkalmazasa, amelyek kereteben villamosenergia-kereskedelem es egyeb kapcsolodo ugyletek kerulhetnek lebonyolitasra szabvanyositott szerződesek formajaban. A vallalkozas egy innovativan műkodő szervezet, mely a szabalyozottsagaval elősegiti a magyarorszagi energiapiac likviditasanak erősiteset, illetve a hatekonysaganak a novekedeset. A vallalkozas fő celja, hogy a referenciaar, illetve a tőzsdei kereskedesi felulet műkodtetesevel hozzajaruljon a szabad piaci kereskedelemhez, valamint a magyarorszagi villamosenergia-piac fejlődesehez. A magyarorszagi villamosenergia kereskedelem akkor tud a jovőben fejlődni, ha az „aramtőzsde” nagyobb mertekben kerul kihasznalasra. Cikkemben a „HUPX” piac gazdasagi jelentőseget kivanom vizsgalni Magyarorszagon hosszu idősorokon keresztul. Fontosnak tartom bemutatni az ugynevezett „masnapi piacot”, illetve a „napon beluli piacot” is, melyek a szabad kereskedelem egyik kilepesi lehetőseget adhatja Magyarorszagnak a jovőben. Szamitasaimban a MAVIR ZRt. (a magyarorszagi Atviteli Rendszeriranyito) altal iranyitott magyar kozcelu halozaton leszallitott villamos energiat vizsgalom. Termeszetesen a villamosenergia piac vizsgalatanal figyelembe veszem a magyar villamosenergia-rendszer Uzemi Szabalyzatanak rendelkezeseit is. Abstract: Currently, it is worth examining the electricity market in Hungary, as there have been changes in the data of the past year. Righ now, the Hungarian electricity market is operated by HUPX ZRt., which is highly recognized in the Central and Eastern European region. The aim of HUPX Ltd. is to operate the organized electricity market in Hungary on the basis of the provisions of the Hungarian Electricity Act and the permits issued by the Hungarian Energy Office. The main purpose of its operation is to use the most modern electricity trading platforms, where electricity trading and other related transactions can be executed in the form of standardized contracts. The enterprise is an innovative organization that, through its regulation, promotes the strengthening of the liquidity of the Hungarian energy market and the increase of its efficiency. The main goal of the company is to contribute to free market trading and the development of the Hungarian electricity market by operating the reference price and the trading market. The electricity trade in Hungary can develop in the future if the power exchange is exploited to a greater extent. In my article I would like to examine the economic importance of the HUPX market in Hungary through long time series. I also consider it important to present the so-called "day-ahead market" and the "day-to-day market", which may give Hungary an opportunity to exit free trade in the future. In my calculations I examine the electricity supplied by the Hungarian public utility network controlled by MAVIR ZRt. (Transmission System Operator in Hungary). Of course, in the examination of the electricity market, I also take into account the provisions of the Operational Rules of the Hungarian Electricity System.

In this paper, we provide an analytical valuation formula for power exchange options with default risk. The proposed model not only considers the correlations among the two underlying assets and the asset of the counterparty, but also allows for the possible default prior to the maturity of the option. We decompose the risk of all assets into idiosyncratic and systematic parts. By means of the measure-change technique, we obtain a pricing formula for power exchange options with default risk. Finally, numerical results are presented to show the power exchange option values.

In this paper, a discrete-time framework is proposed to value power exchange options with counterparty default risk, where counterparty risk is considered in a reduced-form setting and the variance processes of the underlying assets are captured by GARCH processes. In addition, the proposed model allows for the correlation between the intensity of default and the variances of the underlying assets by breaking down the total risk into systematic and idiosyncratic components. By dint of measure-change techniques and characteristic functions, we obtain the closed-form pricing formula for the value of power exchange options with counterparty default risk. Finally, numerical results are presented to show the power exchange option values.

The effectiveness and liquidity of the Power Exchange (PX) has improved since their commencement in 2008. Under the impact of Indian electricity Act 2003, it introduces the open access provision to end up the monopolies that have been adopted by various state electricity boards. The presented work comprises of two parts. The first part includes the current scenario of Indian energy infrastructure. Second part deals with the assessment of the total transacted energy at various contracts of PXs. The various contracts include the day ahead market, term ahead market, renewable energy certificates, and energy saving certificates. The assessment reveals that the total renewable energy source contribution through PXs under the renewable purchase obligation (RPO). Further, the assessment presents the analysis of unmet target of RPOs. Furthermore, we discuss the new norm set by the GoI in order to fulfill the targeted goal of 8% solar based and 11% non-solar RPOs. Moreover, the structure and achievements of energy saving certificates are investigated. The total uncleared transacted electricity volume due to congestion has been shown. Moreover, the detailed steps taken by PXs to handle the risk management is discussed. Keywords: Day-ahead market, Term ahead market, Renewable energy certificates, Energy saving certificates, Short-term power market, Power exchange, Congestion management, Risk management

This paper develops a theoretical framework to analyze the link between real‐time and day‐ahead competition in a hydro‐based wholesale electricity market. Predictions of the model are tested on a detailed data set of trades and prices from the Nordic power exchange, Nord Pool. We study market performance before and after a reform that increased the number of price areas (local markets) in Sweden, and reject the hypothesis of perfect competition in some of the Swedish price areas. Our results suggest that firms exercised some local market power during the sample period.

An equipment capacity configuration method for park-level integrated energy system (PIES) is given in this paper. The power exchange among subsystems is considered in this method when multiple subsystems are operating jointly. Firstly, the structure and model of multi-area PIES is established, respectively. Then, the capacity configuration optimization model of multi-area PIES is established, which can minimize the cost of the system. Finally, the given method’s validity is shown by a case study and shows in this paper.

In this paper, the evaluation of reliability and economic indices of interconnected microgrids (ICMGs) in emergency conditions is done. In this way, exchanged power between microgrids (MGs) in both islanded and grid-connected modes is investigated. A power exchange algorithm based on economic and reliability features is proposed. In this algorithm, exchanged power between MGs based on customer interruption cost (CIC) and electricity prices (EPs) is represented. To evaluate the indices a new method is used, which has high accuracy. The efficiency of the proposed methods is examined for bus-2 of the Roy Billinton distribution System (RBDS) system and different scenarios tackling EP and CIC into the problem formulation. The evaluation results of the new method are compared with the results of the Monte Carlo method.

This paper analyzes the electricity transaction of distributed generation (DG) prosumers under different settlement modes in China. In general, DG prosumers have dual-directional power exchange with power grid and thus participate in both the purchase and sale of electricity, involving in the processes of metering, settlement, and billing. For DG prosumers, this paper presents several metering models, settlement mechanisms, electricity price of feed-in and off-grid. Furthermore, the economic benefits under different settlement modes are compared, including the ‘surplus generation’ and ‘total generation’ feed-in modes in China, and the net energy mode abroad, for DG prosumers, distribution system operator and governmental decision maker. The future challenges about DG prosumer development are discussed.

We review the variational formulation of nonequilibrium thermodynamics as an extension of the Hamilton principle and the Lagrange-d’Alembert principle of classical mechanics. We focus on the case of open systems that include the power exchange due to heat and matter transfer, with special emphasis on reacting systems which are very important in biological science.

The European Target Model for electricity markets has been shaped over the past three decades by successive legislations and reforms with the aim of creating a liberalized integrated market fostering efficient cross border trade and competition. The operation of a single market requires the implementation of harmonized rules across the EU Member States as regards capacity allocation, congestion management and market coupling enabling cross-border exchanges of electricity. To this end, the majority of the EU countries have established organized markets, mainly power exchanges, operating in alignment with the EU Target Model rules facilitating energy transactions in a transparent and reliable manner. In 2020, Greece has adopted the necessary legislative and regulatory acts for the restructuring of the wholesale electricity market including the establishment of the Hellenic Energy Exchange operating the new markets, along with the Transmission System Operator. This thesis explores the EU background on the basis of which this major reform took place and presents the new regulatory framework for the operation of forward, day-ahead, intra-day and balancing markets for electricity, with a focus on the rules for access, participation and clearing of the transactions, followed by an assessment of the first year of the operation of the new markets.

This paper investigates the consequences of future increased transmission capacity between the hydro-based power production system in Scandinavia and the thermal-based power production system in Europe with main focus on impacts on market prices and exchanges between the two systems. One important consequence is a significant reduction of the spot price volatility of power in Scandinavia. Reduced volatility, and thus stable prices, is beneficial to both investors and consumers. In addition to this, the paper deals with reduction of CO2 emissions from the integrated hydro-thermal production system with presentation of two alternative reduction strategies. The paper is based on model simulations with the EMPS model.

Community microgrid can be one of the efficient option for supplying rural loads or local area operation. Community microgrid is the most reliable and economical concept for meeting the current trends along with individual advantages of each microgrid. Community microgrid with the group of hybrid DC/AC microgrids can be connected with suitable techniques for maintaining the quality and continuity of power to the assigned area. These systems may operate either in grid connected or islanded mode. The implementation of community microgrid calls for efficient strategies of power exchange with utility grid and also reliability and stability of interconnected system has to be maintained. This paper discusses the important control and coordinating techniques of community microgrid system.

The prediction of day-ahead electricity prices with higher accuracy is always helpful for the market players of the power exchange. This study was intended in the first place to find out the best time series prediction method for the selected 14 European countries. The test results of four time-series methods show that the next day prices were more in line with the previous day prices in 87% of the selected countries; Later, a classification approach is followed by 33 different features of each country to answer the question of which method would be the best for the other countries, that were not studied in this paper, would be? As a result, the support vector machine algorithm results in 57% accuracy in classifying an unknown European country to determine the best prediction method. Therefore, this paper focuses now on two correlated studies to find out the best time series prediction methods and a classification approach for selected countries.

A highly efficient and compact metamaterial extended interaction oscillator (MEIO) is characterized and designed. The power exchange function of the multiple-gap extended interaction resonant cavity loading the proposed metamaterial is investigated for the π mode. Furthermore, the cavity diameter of 5-gap MEIO is only 37 mm at S-band. The CST PIC simulations show the peak output power of about 10 MW and the electronic efficiency up to 48% at 2.866 GHz when the beam voltage and current are 130 kV and 80 A, respectively, and the focusing magnetic field is 2000 G. The simulation results suggest that the proposed MEIO has the potential application in the future accelerators as an MW-level high-efficiency, miniaturized microwave source.

Electric vehicles have developed rapidly in recent years, and have made tremendous contributions to energy conservation, emission reduction, and green travel. However, the long charging time limits the further promotion of electric vehicles. Based on the idea of power exchange instead of charging, this paper puts forward the design plan of the power station and the battery design program suitable for the power exchange mode. A verification analysis was conducted.

This work introduces and describes the use of the parallel-connected Γ-Z-source power converters (ΓZSPCs) as a new interconnection method for the hybrid microgrids (HMGs) to enhance the reliability and the amount of power exchange between the AC and DC sub-grids. Then an adaptive gain-regulating-based (AGR) control strategy is proposed for the ΓZSPCs. To this end, the instantaneous average current sharing (IACS) strategy is adopted wherein the current controllers use the AGR. The simulation of the proposed interlink topology and the control scheme resulted in the improvement of the power exchange within the HMG and the reduced energy loss.

The MONITA (Montenegro-Italy) High Voltage Direct Current (HVDC) link is the first connection between Italian peninsula and Montenegro. The first pole of the link is in operation since the end of December 2019, this paper describes the main real-time and operational outcomes from the experience earned during the early times after the entry in operation of the link. The article focuses both on market aspects and the operational ones. The MONITA link allows, for the first time, the commercial power exchange across the Adriatic Sea from Italy to Montenegro generating commercial benefit for overall European energy market. The article analyzes the commercial outcomes giving evidence about the statistics of the direction of power flow and the saturation of the capacity of the link. The main technical outcomes are described with respect to the effect on the real time control operation due to the occurred events. Finally, the main strategy to manage the link with the Italian Load Frequency Controller (LFC) is drafted with a focus on N-1 operation.

The growing demand for electric energy and the increasing penetration rate of renewable energy sources have led to the development of regional electricity markets internationally. In this paper, decentralized power exchange scheduling methods are discussed, in terms of tie-lines of interconnected areas, where each area has a separate electricity market. These methods include auxiliary problem principle (APP), optimality condition decomposition (OCD) and alternative direction multiplier (ADM), and it has been tried to compare different aspects of the operation to identify their efficacy under different conditions. The comparisons made in this paper are more comprehensive than previous studies and it has been tried to identify the positive aspects and challenges of each method with respect to network conditions and the superior method for coordinated scheduling of the tie-lines is determined. Simulation studies have been performed on a three-area (triangular structure) test system to create a loop between the intersecting tie-lines. Also, different tie-line capacities between the areas and different choice of references buses are considered. The efficacy of these methods in each case is described.

This paper presents a fuzzy-based power exchange management between two neighboring residential grid-connected microgrids comprising both photovoltaic generation and battery energy storage system (BESS). The proposed power exchange management accounts for the magnitude of the energy rate-of-change of each microgrid and the charge difference between the BESSs of both microgrids to charge the ESS that has an energy deficit. As such, the proposed power exchange management can reduce the amount of power absorbed from the mains of each microgrid by operating jointly with each other rather than separately, and it also synchronizes the ESS of both microgrids, improving the behavior of ESSs. A comparison of the simulated results for a scenario with and without power exchange is presented in order to demonstrate the adequate behavior of the proposed power exchange management. This work is part of the projects 2019-PIC-003-CTE and 2020-EXT-007 from the Research Group of Propagation, Electronic Control, and Networking (PROCONET) of Universidad de las Fuerzas Armadas ESPE. This work has been developed with the support of VLIR-UOS and the Belgian Development Cooperation (DGD) under the project EC2020SIN322A101. This work has been partially supported by the Spanish Ministry of Industry and Competitiveness under the grants DPI2015-67292-R and FEDER ECO 1823-2015.

This study focuses on reduced-order dynamical modelling of droop controlled converter-based DC sub-microgrid (MG) in a hybrid AC/DC MG. In hybrid MGs, electrical power is exchanged between the AC and DC sub-MGs by a bidirectional AC/DC converter. The authors aim to develop a comprehensive reduced-order dynamical model for the DC side in this part, incorporating standard classes of electrical loads including constant current, constant power, and constant resistance loads. Furthermore, dynamical behaviour of the power exchange between the AC and DC sub-MGs is modelled, considering that the bidirectional power converter controller aims to equalise the load ratios of AC and DC sub-MGs in order to facilitate overall decentralised control over the hybrid MG. Analytical derivations of steady-state values of main variables are given and the overall dynamical and algebraic equations are determined. In order to validate the developed model, a hybrid MG is implemented in PSCAD. Then, the proposed model for the case study is implemented in Matlab/Simulink and the results are compared with the PSCAD outputs. The comparative results show the validity of the developed reduced-order comprehensive model. The reduced-order models are preferred in designing observers such as model-based fault detection and diagnosis observers.

An optimization model is formalized for the energy planning of urban districts equipped with renewable energy power plants (photovoltaic fields and wind micro-turbines), combined heat and power units, and traditional boilers; districts are connected to the public distribution grid. The main decision variables of the model are the number and typology of wind turbines and cogeneration plants, the size of photovoltaic fields and the power exchange with the public grid. The optimal values of the variables come from the minimization of installation, maintenance and operational costs, and satisfy load and technical constraints. The model is applied to three districts in the Savona Municipality that represent pilot sites of an extended project concerning the planning and management of smart urban areas. The analysis of different scenarios allows evaluating the role of uncertainties of renewable sources over the optimal solution of the planning problem.

For the first time the limit conditional cycles in P-V and T-S coordinates of the device implementing the stratification effect (TL) for subsonic and supersonic flow regimes have been presented. The analysis of energy efficiency of heat exchange processes in TL on the basis of the developed limit cycles is carried out. As one of the integrative criteria of the device functioning the indicator of power exchange efficiency of the flow machine is offered.

Based on the widely accepted experience of general commodity exchanges and power exchanges, credit management plays an important role in preventing possible risk regarding market credit. The credit management mechanism of Kunming Power Exchange is based on credit evaluation–The exchange scores a market participants credit by evaluating its willingness and ability to perform contracts. The exchange believes that these results reflect their trading performance as well as probability of default, which helps both the exchange and market participants to identify and prevent credit risk. As currently the evaluation rules are not based on historical data, which are not available in the newly established market, their effectiveness needs to be comprehensively analyzed. Several indicators are selected to evaluate the contract fulfillment of the market participants, and the empirical results indicate that there is strong correlation between a participants credit score and its trading performance.

In this paper, a solid-state transformer is studied, which adopts three-stage cascade control of input isolation output. The transformer can provide high-voltage and low-voltage DC bus, which can realize DC input and output of DC, and has strong compatibility. In this paper, the solid-state transformer is taken as the research object, focusing on the energy flow analysis of solid-state transformers and the coordinated control between solid-state transformers. The structure and control strategy of solid-state transformers are studied. The simulation model of solid state transformer is built by using Matlab/Simulink. The simulation results show that the coordinated control strategy system used in this paper has good dynamic performance, good anti-interference and fast response.

Microgrids are becoming popular because of the rise of distributed energy resources (DERs). The quest for efficient utilization of DERs resulted in the development of hybrid dc/ac microgrids, which consist of independent dc and ac subgrids. Controlling the power exchange across hybrid microgrids is an important aspect in maximizing the benefits. There are numerous techniques proposed in the literature to control the power flow; however, most of these techniques use proportional-integral controllers which are difficult to tune and exhibit slow response. To eliminate the drawback of existing control solutions, this letter proposes a novel strategy to exchange active power among dc and ac microgrids. The proposed control strategy is based on the hill climbing algorithm that uses perturbations of power angle δ and observes the corresponding changes in the active power. An average model of the hybrid microgrid is first developed for the evaluation of the proposed algorithm. The proposed algorithm is then applied to verify its effectiveness for achieving sufficient power exchange and enhancing the dynamic response. The model is implemented and tested using MATLAB/Simulink. Moreover, the proposed control strategy is experimentally validated using a real-time simulator, OPAL-RT.

This paper proposes a set of new metrics for quantitatively assessing the performance of multi-microgrid systems which are operated in stand-alone mode. These metrics include generation penetration indices for indicating the configuration of distributed generations and loads, power exchange indices for representing energy interaction among microgrids and with the main grid, as well as reliability and economic indices for quantifying the reliable and economic operation of muti-microgrid systems. A multi-step performance assessment method for multi-microgrid systems is proposed, which considers different reliability requirements and economic characters of critical and non-critical loads as well as the energy exchange among microgrids and with the main grid for effectively calculating the proposed metrics. Case studies with practical data show the effectiveness of the proposed metrics and multi-step performance assessment method for assessing the performance of multi-microgrid systems.

Security constrained multi area multi objective dynamic economic dispatch (SCMAMODED) with renewable energy (RE) and all the possible MTDC stability constraints is formulated for the first time. The stability merits of multi terminal DC (MTDC) tie lines as compared to the traditional HVAC forms the main objective of this paper. Probabilistic load flow (PLF) is applied to determine the system parameters while the uncertainties are modelled using Scenario Based Method (SBM). The simulation results reveal that with the use of MTDC tie lines, the frequency and voltage stability in the MAMODED with renewable energy sources (RES) are enhanced while keeping the MTDC power exchange interface nodes at secure levels.